X-ray photographs viewable in three-dimension have been known in the past. For the most part, the production of such photographs require the use of some type of grating mask which limits the passage of x-rays from a moving x-ray source, such as is provided with an x-ray tomograph, to a photographic film sensitive to the x-rays or to light from an intensifying screen excited by x-rays. Disclosures in this field are found in U.S. Pat. Nos. 1,447,399 and 2,468,963 and in British Pat. No. 621,107. Other disclosures relating to masks for three-dimensional photography include U.S. Pat. Nos. 2,029,300 and 2,214,621.
For the most part, all of these disclosures provide a means which is not completely satisfactory with reference to the quality of the resulting x-ray photograph. Greater quality is to be desired. The poor quality of conventional photographs is considered to be due to the way in which the mask is made and used, the prior masks being of poor quality and design due to secondary radiation which is caused when x-rays strike the material which is opaque to the x-rays themselves. Such secondary radiation sometimes strikes the emulsion of the film to cause diffusion and a poor quality of the resulting image.
Because of these drawbacks, a need has arisen for an improved film and mask which intensifying screen combination permits three-dimensional x-ray photographs to be made with a minimum of x-ray dosage yet the quality of the resulting image is higher than conventionally attainable to provide high quality resolution of said image for immediate viewing and analysis.